Hedgehog pathway inhibitors for locally advanced and metastatic basal cell carcinoma: A real-world single-center retrospective review

Basal cell carcinoma (BCC) is highly curable by surgical excision or radiation. In rare cases, BCC can be locally destructive or difficult to surgically remove. Hedgehog inhibition (HHI) with vismodegib or sonidegib induces a 50-60% response rate. Long-term toxicity includes muscle spasms and weight loss leading to dose decreases. This retrospective chart review also investigates the impact of CoQ10 and calcium supplementation in patients treated with HHI drugs at a single academic medical center from 2012 to 2022. We reviewed the charts of adult patients diagnosed with locally advanced or metastatic BCC treated with vismodegib or sonidegib primarily for progression-free survival (PFS). Secondary objectives included overall survival, BCC-specific survival, time to and reasons for discontinuation, overall response rate, safety and tolerability, use of CoQ10 and calcium supplements, and insurance coverage. Of 55 patients assessable for outcome, 34 (61.8%) had an overall clinical benefit, with 25 (45.4%) having a complete response and 9 (16.3%) a partial response. Stable disease was seen in 14 (25.4%) and 7 (12.7%) progressed. Of the 34 patients who responded to treatment, 9 recurred. Patients who were rechallenged with HHI could respond again. The median overall BCC-specific survival rate at 5 years is 89%. Dose reductions or discontinuations for vismodegib and sonidegib occurred in 59% versus 24% of cases, or 30% versus 9% of cases, respectively. With CoQ10 and calcium supplementation, only 17% required a dose reduction versus 42% without. HHI is highly effective for treating advanced BCC but may require dosing decreases. Sonidegib was better tolerated than vismodegib. CoQ10 and calcium supplementation can effectively prevent muscle spasms.

Vulvar Cancer, Version 3.2024, NCCN Clinical Practice Guidelines in Oncology

Vulvar cancer is annually diagnosed in an estimated 6,470 individuals and the vast majority are histologically squamous cell carcinomas. Vulvar cancer accounts for 5% to 8% of gynecologic malignancies. Known risk factors for vulvar cancer include increasing age, infection with human papillomavirus, cigarette smoking, inflammatory conditions affecting the vulva, and immunodeficiency. Most vulvar neoplasias are diagnosed at early stages. Rarer histologies exist and include melanoma, extramammary Paget's disease, Bartholin gland adenocarcinoma, verrucous carcinoma, basal cell carcinoma, and sarcoma. This manuscript discusses recommendations outlined in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for treatments, surveillance, systemic therapy options, and gynecologic survivorship.

Association Between Pretreatment Chest Imaging and Immune Checkpoint Inhibitor Pneumonitis Among Patients With Lung Cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) are a first-line and perioperative treatment for lung cancer. Pneumonitis is a potentially life-threatening complication of ICI treatment in 2% to 5% of patients; however, risk factors for developing ICI pneumonitis (ICI-p) remain undefined.

METHODS

We conducted a retrospective cohort study of consecutive patients with lung cancer who received at least one dose of ICI from 2015 through 2020 at The Ohio State University. Pneumonitis cases were documented by the treating oncologist and retrospectively evaluated for agreement between an oncologist and a pulmonologist. Patient demographic and clinical characteristics were recorded and summarized between those with and without pneumonitis for the overall cohort. Univariate and multivariable survival analyses using the Fine-Gray competing risk model were used to examine the associations.

RESULTS

A total of 471 patients with lung cancer were included, of which 402 had non-small cell lung cancer and 69 had small cell lung cancer; 39 (8%) patients in the overall cohort developed ICI-p. Preexisting interstitial abnormalities and prior chest radiation were both significantly associated with ICI-p on univariate analysis (hazard ratio [HR], 8.91; 95% CI, 4.69-16.92; P<.001; and HR, 2.81; 95% CI, 1.50-5.28; P=.001). On multivariable analyses, interstitial abnormalities remained a strong independent risk factor for ICI-p when controlling for chest radiation and type of immunotherapy (HR, 9.77; 95% CI, 5.17-18.46; P<.001). Among patients with ICI-p (n=39), those with severe (grade 3-5) pneumonitis had worse overall survival compared with those with mild (grade 1 or 2) pneumonitis (P=.001). Abnormal pulmonary function test results at both 12 and 18 months prior to ICI initiation were not significantly associated with ICI-p.

CONCLUSIONS

Preexisting interstitial abnormalities on chest CT and prior chest radiation are independent risk factors that are strongly associated with ICI-p in patients with lung cancer. These findings highlight a potential need for closer observation for ICI-p among patients with these risk factors.

Association between pre-treatment chest imaging and pulmonary function abnormalities and immune checkpoint inhibitor pneumonitis

BACKGROUND

Immune checkpoint inhibitors (ICIs) are a first-line treatment for various metastatic solid tumors. Pneumonitis is a potentially devastating complication of ICI treatment and a leading cause of ICI-related mortality. Here, we evaluate whether abnormal pre-treatment pulmonary function tests (PFTs) or interstitial abnormalities on computed tomography of the chest (CT chest) prior to ICI are associated with the development of ICI-pneumonitis (ICI-p).

METHODS

We conducted a retrospective cohort study of consecutive patients who received at least one dose of ICI from 2011 to 2017 at The Ohio State University. Potential risk factors for ICI-p, including abnormal PFTs and CT chest, were recorded. These risk factors were compared between patients with and without pneumonitis.

RESULTS

In total, 1097 patients were included, 46 with ICI-p and 1051 without. Ninety percent of patients had pre-treatment chest imaging, while only 10% had pre-treatment PFTs. On multivariable analysis, interstitial abnormalities and reduced total lung capacity (TLC) were significantly associated with development of ICI-p (hazard ratio of 42.42 [95% CI; 15.04-119.67] and hazard ratio of 4.04 [95% CI; 1.32-12.37]), respectively. No other PFT abnormality was associated with increased risk of ICI-p. There was no significant difference in overall survival in patients who did or did not develop ICI-p (p = 0.332).

CONCLUSIONS

Pre-existing interstitial abnormalities on CT chest and reduced TLC were strongly associated with developing ICI-p. Prospective studies are warranted to further explore the role of PFTs as a potential tool for identifying patients at highest risk for developing ICI-p.

Immune checkpoint inhibitor-induced hepatitis injury: risk factors, outcomes, and impact on survival

PURPOSE

Immune checkpoint inhibitors (ICIs) are associated with a unique set of immune-related adverse events (irAEs). Few studies have evaluated the risk factors and outcomes of patients who develop ICI-induced hepatitis (ICIH).

METHODS

We utilized an institutional database of patients with advanced cancers treated with ICI to identify patients with ICIH. irAEs were graded using the Common Terminology Criteria for Adverse Events v4. Overall survival (OS) was calculated from the date of ICI to death from any cause or the date of the last follow-up. OS with 95% confidence intervals were estimated using the Kaplan-Meier method and stratified by the occurrence of ICIH.

RESULTS

We identified 1096 patients treated with ICI. The most common ICIs were PD1/L1 (n = 774) and CTLA-4 inhibitors (n = 195). ICIH occurred among 64 (6%) patients: severity was < grade 3 in 30 and ≥ grade 3 in 24 patients (3.1% overall). Median time to ICIH was 63 days. ICIH was more frequent in women (p = 0.038), in patients treated with combination ICIs (p < 0.001), and when given as first-line therapy (p = 0.018). Occurrence of ICIH was associated with significantly longer OS, median 37.0 months (95% CI 21.4, NR) compared to 11.3 months (95% CI 10, 13, p < 0.001); there was no difference in OS between patients with ≥ grade 3 ICIH vs grade 1-2.

CONCLUSIONS

Female sex, combination immunotherapy, and the first line of immunotherapy were associated with ICIH. Patients with ICIH had improved clinical survival compared to those that did not develop ICIH. There is a need for prospective further studies to confirm our findings.

Abstract 3764: Expression patterns of microRNAs and associated target genes in ulcerated primary cutaneous melanoma

Tumor ulceration in cutaneous melanoma represents one of the top prognostic indicators for clinical outcome, associated with reduced progression free and overall survival. Despite this influence, the underlying biology driving tumor ulceration remains largely unexplored. One of the potential mediators of ulceration are microRNAs (miRNAs). These short, non-coding RNAs are frequently dysregulated in cancer and can impact tumor biology via mediation of gene expression. Distinct miRNA expression patterns have been identified in melanoma that can function as predictive biomarkers of disease progression and metastasis. However, the presence of a unique miRNA profile in ulcerated melanoma has not yet been assessed.

miRNA and mRNA expression was assessed in 35 ulcerated and non-ulcerated cutaneous melanomas using the NanoString Human miRNA and Tumor Signaling 360 mRNA assays and validated in an independent cohort. Linear models and moderated t-tests were used to detect differential expression between ulcerated and non-ulcerated tumors. Pathway enrichment and functional annotations were determined using public databases. Pearson correlations were employed to predict miRNA-mRNA binding pairs. Differentially expressed mRNAs were identified as miRNA targets using Ingenuity Pathway Analysis.

Comparison between groups revealed significant upregulation of 13 miRNAs in ulcerated relative to non-ulcerated tumors (p &lt;0.03). 4 of these miRNAs were also significantly upregulated in the validation cohort (miR-363-3p, miR-196b-5p, miR-135b-5p and miR-223-3p, p &lt;0.02). Conversely, 11 miRNAs were significantly downregulated in ulcerated relative to non-ulcerated tumors (p &lt;0.05), of which, miR-376c-5p was also significantly downregulated in the validation cohort (p=0.009). 21 mRNAs were differentially expressed in ulcerated relative to non-ulcerated tumors, with 3 being significant in the validation cohort as well (FPR, IL-11, and ADM, p &lt;0.05). 9 of these 21 mRNAs were then identified as predicted targets of multiple differentially expressed miRNAs in ulcerated tumors. 2 of the differentially expressed mRNAs had an inverse correlation in expression with regulatory miRNAs in our tumor samples (SOCS3 and miR-218-5p, and IL7R and miR-376c-5p). Each of the mRNAs significantly upregulated in both the original and validation cohorts have been previously associated with angiogenesis, migration or pro-metastatic cell survival in the context of cancer and pathway analysis identified significant enrichment for “granulocyte adhesion and diapedesis” (p=0.02) in ulcerated tumors.

This study demonstrates that a unique subset of miRNAs and mRNAs are differentially expressed in ulcerated melanoma when compared to non-ulcerated. These findings also provide novel insight regarding how increased angiogenesis and metastasis may contribute to melanoma tumor ulceration.

Citation Format: Emily Schwarz, Mallory J. DiVincenzo, Casey Ren, Zoe Barricklow, Maribelle Moufawad, Lianbo Yu, Paolo Fadda, Colin Angell, Sara Zelinskas, Steven Sun, John H. Howard, Catherine Chung, Craig Slingluff, Alejandro A. Gru, Kari Kendra, William E. Carson. Expression patterns of microRNAs and associated target genes in ulcerated primary cutaneous melanoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3764.

Abstract 4527: CD8 T cell-melanoma cell interactions in response and resistance to ipilimumab plus nivolumab: Biopsy analysis of SWOG S1616

Background: In the randomized S1616 trial (NCT03033576), patients with metastatic melanoma refractory to anti-PD-1-based therapy had improved progression free survival (PFS, HR = 0.63, p = 0.037) and objective response to ipilimumab plus nivolumab (ipi/nivo, RR 28%) compared to ipilimumab alone (ipi, RR = 9%). We hypothesized that reversal of resistance to PD-1 blockade with CTLA-4 blockade would result in increased CD8 T-cell infiltration in patient biopsies.

Methods: Multiplex ion beam imaging (MIBI) for 32 protein markers, spanning tumor, immune, and stromal cell types, was used to evaluate the tumor microenvironment in melanoma tumor biopsies collected at baseline (N=21 samples) and one month on-treatment (N=22; N=16 paired timepoints). Tumor-immune cell dynamics were determined by comparing baseline and on-treatment biopsies within clinical groups (ipi/nivo response, N=10; ipi/nivo no-response, N=9; ipi no-response, N=8).

Results: Multiplex analysis in ipi/nivo responsive patients demonstrated increased proportions of CD8 (median 1.6X increase), CD4 (2.1X), regulatory T cells (1.6X), and monocytes (1.4X), with a paralleled 8.1X decrease in melanoma cells over the course of treatment. This was confirmed by histopathologic evidence of tumor regression, necrosis, and immune infiltrate in on-treatment, responding tumor biopsies, as determined by dermatopathologists. Melanoma cells had direct, cell-membrane interactions with CD8 T cells in ipi/nivo responsive patients, both at baseline (median 26%) and on-treatment (median 86%). The shared interface between melanoma and CD8 T-cells had polarized expression of CD3, CD8, and CD45RO. There was no change in T-cell infiltration nor tumor cell content over the course of treatment in ipi/nivo non-responders nor ipi non-responders; similar proportions of melanoma cells were interacting with CD8 T-cells at baseline (median 24%) and on-treatment (27%).

Conclusion: Reversal of resistance to PD-1 blockade is associated with increased frequency of CD8 T-melanoma cell interactions and pathological response, reflective of different stages of antitumor immune responses. Response to ipi/nivo in the anti-PD-1 refractory setting was further associated with increased tumor-polarized and activated CD8 T cells interacting with melanoma cells, demonstrated by the colocalized expression of immune synapse proteins at tumor-CD8-T-cell membrane interfaces.

Citation Format: Katie M. Campbell, Lawrence Kuklinski, Zaid Bustami, Jessica Maxey, Egmidio Medina, Sandra Santulli-Marotto, Cynthia R. Gonzalez, Nataly Naser Aldeen, Kari Kendra, Sapna Patel, Siwen Hu-Lieskovan, James Moon, Shay Bellasea, Christine N. Spencer, Marshall A. Thompson, Michael Wu, Ari Vanderwalde, Philip O. Scumpia, Antoni Ribas. CD8 T cell-melanoma cell interactions in response and resistance to ipilimumab plus nivolumab: Biopsy analysis of SWOG S1616. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4527.

Expression Patterns of microRNAs and Associated Target Genes in Ulcerated Primary Cutaneous Melanoma

Ulcerated cutaneous melanoma carries a poor prognosis, and the underlying biology driving its aggressive behavior is largely unexplored. MicroRNAs (miRs) are small, noncoding RNAs that inhibit the expression of specific genes and exhibit dysregulated expression patterns in cancer. We hypothesized that a unique miR profile exists in ulcerated relative to nonulcerated melanoma and that miR expression inversely correlates with target genes of biologic importance. Expression of miRs and mRNAs was assessed in ulcerated and nonulcerated cutaneous melanomas using the NanoString Human miRNA and Tumor Signaling 360 mRNA assays and validated in an independent cohort. Pathway enrichment and functional annotations for differentially expressed miRs and mRNAs were determined using publicly available databases. Pearson correlations were employed to predict potential miR‒mRNA binding pairs. Ulcerated melanoma tissue showed at least 1.5-fold change in relative expression of 24 miRs, including miR-206, miR-1-3p, and miR-4286 (>2.25-fold decrease, P < 0.048) and miR-146a-5p, miR-196b-5p, and miR-363-3p (>2.5-fold increase, P < 0.014). Ulcerated melanomas also had 21 differentially expressed mRNAs relative to nonulcerated tumors (P < 0.01), among which two had an inverse correlation in expression with regulatory miRs (SOCS3 and miR-218-5p and IL7R and miR-376c-5p). This miR expression profile adds to the molecular characterization of the poorly understood histopathologic phenotype of ulcerated melanoma.

Effectiveness of Adjuvant Pembrolizumab vs High-Dose Interferon or Ipilimumab for Quality-of-Life Outcomes in Patients With Resected Melanoma: A Secondary Analysis of the SWOG S1404 Randomized Clinical Trial

Importance

A key issue for the adjuvant treatment of patients with melanoma is the assessment of the effect of treatment on relapse, survival, and quality of life (QOL).

Objective

To compare QOL in patients with resected melanoma at high risk for relapse who were treated with adjuvant pembrolizumab vs standard of care with either ipilimumab or high-dose interferon α 2b (HDI).

Design, Setting, and Participants

The S1404 phase 3 randomized clinical trial was conducted by the SWOG Cancer Research Network at 211 community/academic sites in the US, Canada, and Ireland. Patients were enrolled from December 2015 to October 2017. Data analysis for this QOL substudy was completed in March 2022. Overall, 832 patients were evaluable for the primary QOL end point.

Interventions

Patients were randomized (1:1) to treatment with adjuvant pembrolizumab vs standard of care with ipilimumab/HDI.

Main Outcomes and Measures

Quality of life was assessed for patients at baseline and cycles 1, 3, 5, 7, and 9 after randomization using the Functional Assessment of Cancer Therapy (FACT) Biological Response Modifiers (FACT-BRM), FACT-General, Functional Assessment of Chronic Illness Therapy-Diarrhea, and European QOL 5-Dimension 3-Level scales. The primary end point was the comparison by arm of cycle 3 FACT-BRM trial outcome index (TOI) scores using linear regression. Linear-mixed models were used to evaluate QOL scores over time. Regression analyses included adjustments for the baseline score, disease stage, and programmed cell death ligand 1 status. A clinically meaningful difference of 5 points was targeted.

Results

Among 1303 eligible patients (median [range] age, 56.7 [18.3-86.0] years; 524 women [40.2%]; 779 men [59.8%]; 10 Asian [0.8%], 7 Black [0.5%], 44 Hispanic [3.4%], and 1243 White [95.4%] individuals), 1188 (91.1%) had baseline FACT-BRM TOI scores, and 832 were evaluable at cycle 3 (ipilimumab/HDI = 267 [32.1%]; pembrolizumab = 565 [67.9%]). Evaluable patients were predominantly younger than 65 years (623 [74.9%]) and male (779 [58.9%]). Estimates of FACT-BRM TOI cycle 3 compliance did not differ by arm (ipilimumab/HDI, 96.0% vs pembrolizumab, 98.3%; P = .25). The adjusted cycle 3 FACT-BRM TOI score was 9.6 points (95% CI, 7.9-11.3; P < .001) higher (better QOL) for pembrolizumab compared with ipilimumab/HDI, exceeding the prespecified clinically meaningful difference. In linear-mixed models, differences by arm exceeded 5 points in favor of pembrolizumab through cycle 7. In post hoc analyses, FACT-BRM TOI scores favored the pembrolizumab arm compared with the subset of patients receiving ipilimumab (difference, 6.0 points; 95% CI, 4.1-7.8; P < .001) or HDI (difference, 17.0 points; 95% CI, 14.6-19.4; P < .001).

Conclusions and Relevance

This secondary analysis of a phase 3 randomized clinical trial found that adjuvant pembrolizumab improved QOL vs treatment with adjuvant ipilimumab or HDI in patients with high-risk resected melanoma.

Trial Registration

ClinicalTrials.gov identifier: NCT02506153.

Combined nivolumab and ipilimumab with or without stereotactic body radiation therapy for advanced Merkel cell carcinoma: a randomised, open label, phase 2 trial

BACKGROUND

Merkel cell carcinoma is among the most aggressive and lethal of primary skin cancers, with a high rate of distant metastasis. Anti-programmed death receptor 1 (anti-PD-1) and programmed death ligand 1 (PD-L1) monotherapy is currently standard of care for unresectable, recurrent, or metastatic Merkel cell carcinoma. We assessed treatment with combined nivolumab plus ipilimumab, with or without stereotactic body radiotherapy (SBRT) in patients with advanced Merkel cell carcinoma as a first-line therapy or following previous treatment with anti-PD-1 and PD-L1 monotherapy.

METHODS

In this randomised, open label, phase 2 trial, we randomly assigned adults from two cancer sites in the USA (one in Florida and one in Ohio) to group A (combined nivolumab and ipilimumab) or group B (combined nivolumab and ipilimumab plus SBRT) in a 1:1 ratio. Eligible patients were aged at least 18 years with histologically proven advanced stage (unresectable, recurrent, or stage IV) Merkel cell carcinoma, a minimum of two tumour lesions measureable by CT, MRI or clinical exam, and tumour tissue available for exploratory biomarker analysis. Patients were stratified by previous immune-checkpoint inhibitor (ICI) status to receive nivolumab 240 mg intravenously every 2 weeks plus ipilimumab 1 mg/kg intravenously every 6 weeks (group A) or the same schedule of combined nivolumab and ipilimumab with the addition of SBRT to at least one tumour site (24 Gy in three fractions at week 2; group B). Patients had to have at least two measurable sites of disease so one non-irradiated site could be followed for response. The primary endpoint was objective response rate (ORR) in all randomly assigned patients who received at least one dose of combined nivolumab and ipilimumab. ORR was defined as the proportion of patients with a complete response or partial response per immune-related Response Evaluation Criteria in Solid Tumours. Response was assessed every 12 weeks. Safety was assessed in all patients. This trial is registered with ClinicalTrials.gov, NCT03071406.

FINDINGS

50 patients (25 in both group A and group B) were enrolled between March 14, 2017, and Dec 21, 2021, including 24 ICI-naive patients (13 [52%] of 25 group A patients and 11 [44%] of 25 group B patients]) and 26 patients with previous ICI (12 [48%] of 25 group A patients and 14 [56%] of 25 group B patients]). One patient in group B did not receive SBRT due to concerns about excess toxicity. Median follow-up was 14·6 months (IQR 9·1-26·5). Two patients in group B were excluded from the analysis of the primary endpoint because the target lesions were irradiated and so the patients were deemed non-evaluable. Of the ICI-naive patients, 22 (100%) of 22 (95% CI 82-100) had an objective response, including nine (41% [95% CI 21-63]) with complete response. Of the patients who had previously had ICI exposure, eight (31%) of 26 patients (95% CI 15-52) had an objective response and four (15% [5-36]) had a complete response. No significant differences in ORR were observed between groups A (18 [72%] of 25 patients) and B (12 [52%] of 23 patients; p=0·26). Grade 3 or 4 treatment-related adverse events were observed in 10 (40%) of 25 patients in group A and 8 (32%) of 25 patients in group B.

INTERPRETATION

First-line combined nivolumab and ipilimumab in patients with advanced Merkel cell carcinoma showed a high ORR with durable responses and an expected safety profile. Combined nivolumab and ipilimumab also showed clinical benefit in patients with previous anti-PD-1 and PD-L1 treatment. Addition of SBRT did not improve efficacy of combined nivolumab and ipilimumab. The combination of nivolumab and ipilimumab represents a new first-line and salvage therapeutic option for advanced Merkel cell carcinoma.

FUNDING

Bristol Myers Squibb Rare Population Malignancy Program.

Treatment of Brain Metastases: The Synergy of Radiotherapy and Immune Checkpoint Inhibitors

Brain metastases are a devastating sequela of common primary cancers (e.g., lung, breast, and skin) and have limited effective therapeutic options. Previously, systemic chemotherapy failed to demonstrate significant benefit in patients with brain metastases, but in recent decades, targeted therapies and more recently immune checkpoint inhibitors (ICIs) have yielded promising results in preclinical and clinical studies. Furthermore, there is significant interest in harnessing the immunomodulatory effects of radiotherapy (RT) to synergize with ICIs. Herein, we discuss studies evaluating the impact of RT dose and fractionation on the immune response, early studies supporting the synergistic interaction between RT and ICIs, and ongoing clinical trials assessing the benefit of combination therapy in patients with brain metastases.

Abstract CT013: S1616: Ipilimumab plus nivolumab versus ipilimumab alone in patients with metastatic or unresectable melanoma that did not respond to anti-PD-1 therapy

Background: Patients with advanced melanoma primarily refractory to single agent PD-1 blockade therapy have an option of receiving the CTLA-4 blocking antibody ipilimumab, but if ipilimumab should be given as a single agent or in combination with the anti-PD-1 nivolumab has not been established prospectively.

Methods: Patients aged &gt;18 with metastatic or unresectable melanoma without objective response to anti-PD-1 therapy given without CTLA-4 therapy were randomized 3:1 to receive either ipilimumab 3mg/kg + nivolumab 1mg/kg q3 wks x4 cycles followed by nivolumab 480mg q4wks (ipi/nivo) up to 2 years, or ipilimumab 3mg/kg q3weeks x4 cycles (ipi). Additional key eligibility criteria included ECOG Performance Statue (PS) 0-2, no active central nervous system metastases, autoimmune disease, or need for steroids at doses of &gt;10 mg of prednisone or the equivalent. The primary endpoint was progression free survival (PFS). Disease assessments were performed every 12 weeks until progression. Secondary endpoints included overall survival (OS), objective response rate (ORR), and toxicity. All patients were to submit a fresh tumor biopsy and whole blood for correlative endpoints prior to cycle 1 and again at week 5.

Results: 92 eligible patients were enrolled, 69 to ipi/nivo, 23 to ipi. Median age was 64 and 69 in the ipi/nivo and ipi arm respectively. 67% and 65% were male. 65% of patients in both arms had ECOG PS of 0. With a median follow up of 25.3 months, the hazard ratio (HR) for PFS was 0.63 (90% CI 0.41, 0.97) with a statistically significant 1-sided p-value of 0.04 favoring ipi/nivo. The 6-month PFS estimates were 34% (90% CI: 25%-44%) and 13% (4%-27%) for ipi/nivo and ipi respectively. ORR was 28% for ipi/nivo (95% CI 17%-40%) and 9% for ipi (95% CI: 3%-34%). With a median follow up of 24.4 months, 39/69 patients in the ipi/nivo arm and 12/23 patients in the ipi arm had died. 12-month OS was 63% (90% CI 52%-72%) in the ipi/nivo arm and 57% (38%-71%) months in the ipi arm. HR for OS was 0.94 (90% CI 0.54, 1.62) in favor of ipi/nivo with a p-value of 0.42. Adverse event rates were similar in both arms. One treatment related death was reported in the ipi/nivo arm due to disseminated intravascular coagulation and one treatment related death was reported in the ipi arm due to colonic perforation.

Conclusions: This is the first prospective randomized study comparing ipi/nivo to ipi alone in patients with melanoma without response to anti-PD1 therapy. Ipi/nivo was associated with improved progression free survival as compared to ipi alone. The response rate of 28% to ipi/nivo as compared to 9% to ipi alone implies that patients who do not respond to PD-1 alone can be rescued with ipi/nivo. The toxicity of combination therapy was manageable. Ipi/nivo is an appropriate standard in patients with metastatic melanoma who do not respond to single-agent PD-1 therapy. ClinicalTrials.gov Identifier: NCT03033576

Funding: NIH/NCI grants: U10CA180888, U10CA180819, U10CA180821, U10CA180868; Other grants: SU2C-AACR-CT06-17

Citation Format: Ari M. Vanderwalde, James Moon, Kari Kendra, Nikhil I. Khushalani, Frances Collichio, Jeffrey A. Sosman, Alexandra Ikeguchi, Adrienne I. Victor, Thach-Giao Truong, Bartosz Chmielowski, David C. Portnoy, Michael C. Wu, Kenneth F. Grossmann, Antoni Ribas. S1616: Ipilimumab plus nivolumab versus ipilimumab alone in patients with metastatic or unresectable melanoma that did not respond to anti-PD-1 therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT013.

Adjuvant Pembrolizumab versus IFNα2b or Ipilimumab in Resected High-Risk Melanoma

We conducted a randomized phase III trial to evaluate whether adjuvant pembrolizumab for one year (647 patients) improved recurrence-free survival (RFS) or overall survival (OS) in comparison with high-dose IFNα-2b for one year or ipilimumab for up to three years (654 patients), the approved standard-of-care adjuvant immunotherapies at the time of enrollment for patients with high-risk resected melanoma. At a median follow-up of 47.5 months, pembrolizumab was associated with significantly longer RFS than prior standard-of-care adjuvant immunotherapies [HR, 0.77; 99.62% confidence interval (CI), 0.59-0.99; P = 0.002]. There was no statistically significant association with OS among all patients (HR, 0.82; 96.3% CI, 0.61-1.09; P = 0.15). Proportions of treatment-related adverse events of grades 3 to 5 were 19.5% with pembrolizumab, 71.2% with IFNα-2b, and 49.2% with ipilimumab. Therefore, adjuvant pembrolizumab significantly improved RFS but not OS compared with the prior standard-of-care immunotherapies for patients with high-risk resected melanoma.

SIGNIFICANCE

Adjuvant PD-1 blockade therapy decreases the rates of recurrence, but not survival, in patients with surgically resectable melanoma, substituting the prior standard-of-care immunotherapies for this cancer. See related commentary by Smithy and Shoushtari, p. 599. This article is highlighted in the In This Issue feature, p. 587.

686 Characterization of a novel compound that inhibits peroxynitrite generation by myeloid derived suppressor cells

Background

Myeloid-derived suppressor cells (MDSC) are immature immune cells that suppress immunity and mediate resistance to immune–based cancer therapies. MDSC exert their immunosuppressive effects partly through the production of reactive nitrogen and oxygen species, which combine to form peroxynitrite (PNT). PNT reacts with the tyrosine residues of key immune cell signaling proteins and inactivates them via nitration. Targeting MDSC via PNT inhibitors is an attractive avenue to improve the response to immunotherapy. The Peterson and Carson Labs have collaborated to develop a novel inhibitor of PNT and have explored its use in murine tumor models and human patients with cancer.

Methods

Splenocytes (comprised of 12% MDSC) were isolated from mice bearing tumors derived from the EMT6 breast cancer cell line and cultured with 10 µm beads labelled with polyclonal antibodies (immunoglobulin-G or IgG). Fluorescence emitted upon MDSC recognition and reaction with IgG was detected with a previously reported fluorescent sensor compound termed PS3. Cells were mixed with PS3 and IgG beads (or controls: IgG without beads and beads without IgG) and treated for 4 hours with the following agents: (1) BRP0112233, a novel biaryl furan discovered via high-throughput screening using PNT depletion as the readout (6 or 12 µM); (2) Ibrutinib, an FDA-approved Bruton's tyrosine kinase inhibitor shown by the Carson Lab to inhibit the activity of nitric oxide synthase in MDSC, (2, 10 µM); and (3) PBS control. Fluorescence produced by reaction of PS3 with PNT was measured in triplicate wells using a Clariostar plate reader.

Results

Splenocytes from tumor-bearing mice produced significantly greater levels of PNT than normal splenocytes (24-fold vs 8-fold increase over plain beads, p<0.0001). Differences in fluorescence were confirmed via confocal microscopy. BRP0112233 inhibited PNT levels by 40% and 85% for the 6 and 12 µM doses, respectively. Ibrutinib inhibited PNT output by 90% and 100% at 2 and 10 µM. Cell viability was >90% except for the higher BRP dose (60% viability). In humans, peripheral blood mononuclear cells (PBMC) isolated from patients with cancer produced more PNT than healthy donor PBMC.

Conclusions

PNT output could be reproducibly quantified via this assay and BRP0112233 and ibrutinib greatly inhibited MDSC PNT production. Using the EMT6 model, these compounds are being tested in combination with anti-PD-1 antibodies approved for patients with cancer. This assay has shown similar results in human peripheral blood mononuclear cells isolated from patients with cancer.

Acknowledgements

We thank the NIH (NCI UM1 CA186712, R01CA211720), a OSUCCC Translational Therapeutics Seed Grant, and the Pelotonia Fellowship Program for financial support.

687 MDSC gene expression analysis in patients with cancer and the response to inhibition of Bruton's tyrosine kinase

Background

Myeloid-derived suppressor cells (MDSC) are an immunosuppressive immature population of myeloid cells that are elevated in cancer patients. Increased levels of MDSC has been linked to dysregulated anti-tumor responses and reduced efficacy of immune checkpoint therapies thus making them an attractive target. MDSC express Bruton's tyrosine kinase (BTK) and can be depleted using ibrutinib, an FDA-approved irreversible inhibitor of BTK. BTK inhibition leads to reduced MDSC expansion/function in murine models and significantly improved activity of anti-PD-1 antibodies. In this study, single cell RNA-seq (scRNA-seq) was used to characterize the gene expression of MDSC from different cancer types and the effect of ibrutinib on MDSC gene expression.

Methods

Peripheral blood mononuclear cells were isolated from patients with melanoma (n=2), head & neck (n=1), and breast cancer (n=1). MDSC were isolated via fluorescence activated cell sorting. MDSC isolated from melanoma patients (n=2) were treated in vitro for 4h with 1 uM ibrutinib or DMSO and scRNA-seq was performed using the Chromium 10x Genomics platform. ScRNA-seq samples were analyzed using the standard integrative workflow of Seurat v3, which addresses the sample heterogeneity. Cell clusters were identified using Seurat and annotated using SingleRversion3.12. Identification of gene markers for each cell cluster and cell-cluster-specific differential expression analyses were conducted using Seurat.

Results

Baseline gene expression of MDSC from patients with breast and head & neck cancer revealed similarities among the top expressed genes (S100A8, VCAN, and LYZ). In vitro ibrutinib treatment of MDSC from patients with melanoma resulted in significant changes in gene expression within the MDSC cluster compared to DMSO treatment. GBP1(-1.72 log fold change), IL 1β(-1.27 log fold change), and CXCL8(-0.63 log fold change) were among the top downregulated genes (p<0.001) and RGS2 (0.68 log fold change) and ABHD5(0.52 log fold change) were among the top upregulated genes (p<0.001). MDSC subset (PMN-MDSC, M-MDSC, early-MDSC, and CD14+/CD15+ double positive) gene expression changes mirrored total MDSC gene changes. Ingenuity pathway analysis revealed significant downregulated pathways including TREM1 (p<0.001), nitric oxide signaling (p<0.003), and IL-6 signaling (p<0.004). Multiple genes associated with cellular movement (CXCL8, CXCL10) and activation of macrophages (CXCL10, CCL3) were downregulated (p<0.001). PCR analysis on isolated melanoma MDSC (n=2) treated in vitro with ibrutinib verified downregulation of CXCL8 (0.42 fold decrease, p<0.05) and CXCL10 (0.40 fold decrease, p<0.001).

Conclusions

Analysis via scRNA-seq revealed similar gene expression patterns for MDSC from different cancer patients. There was downregulation of multiple genes and pathways important to MDSC function and migration after BTK inhibition.

Ethics Approval

The study obtained ethics approval.

IRB# 1999C0348

Effect of Immune Checkpoint Blockade on Myeloid-Derived Suppressor Cell Populations in Patients With Melanoma

Introduction

Myeloid-derived suppressor cells (MDSC) are a subset of immature myeloid cells that inhibit anti-tumor immunity and contribute to immune therapy resistance. MDSC populations were measured in melanoma patients receiving immune checkpoint inhibitors (ICI).

Methods

Patients with melanoma (n=128) provided blood samples at baseline (BL), and before cycles 2 and 3 (BC2, BC3). Peripheral blood mononuclear cells (PBMC) were analyzed for MDSC (CD33⁺/CD11b⁺/HLA- DR^lo/-) and MDSC subsets, monocytic (CD14+, M-MDSC), granulocytic (CD15+, PMN-MDSC), and early (CD14-/CD15-, E-MDSC) via flow cytometry. Statistical analysis employed unpaired and paired t-tests across and within patient cohorts.

Results

Levels of MDSC as a percentage of PBMC increased during ICI (BL: 9.2 ± 1.0% to BC3: 23.6 ± 1.9%, p<0.0001), and patients who developed progressive disease (PD) had higher baseline MDSC. In patients who had a complete or partial response (CR, PR), total MDSC levels rose dramatically and plateaued (BL: 6.4 ± 1.4%, BC2: 26.2 ± 4.2%, BC3: 27.5 ± 4.4%; p<0.0001), whereas MDSC rose less sharply in PD patients (BL: 11.7 ± 2.1%, BC2: 18.3 ± 3.1%, BC3: 19.0 ± 3.2%; p=0.1952). Subset analysis showed that within the expanding MDSC population, PMN-MDSC and E-MDSC levels decreased, while the proportion of M-MDSC remained constant during ICI. In PD patients, the proportion of PMN-MDSC (as a percentage of total MDSC) decreased (BL: 25.1 ± 4.7%, BC2: 16.1 ± 5.2%, BC3: 8.6 ± 1.8%; p=0.0105), whereas a heretofore under-characterized CD14+/CD15+ double positive MDSC subpopulation increased significantly (BL: 8.7 ± 1.4% to BC3: 26.9 ± 4.9%; p=0.0425).

Conclusions

MDSC levels initially increased significantly in responders. PMN-MDSC decreased and CD14+CD15+ MDSC increased significantly in PD patients. Changes in MDSC levels may have prognostic value in ICI.

Immune checkpoint inhibitor-related thrombocytopenia: incidence, risk factors and effect on survival

INTRODUCTION

Immune checkpoint inhibitors (ICI) are associated with unique immune-related adverse events (irAEs). Immune-related thrombocytopenia (irTCP) is an understudied and poorly understood toxicity; little data are available regarding either risk of irTCP or the effect of irTCP on clinical outcomes of patients treated with ICI.

METHODS

We conducted a retrospective review of sequential cancer patients treated with ICI between 2011 and 2017 at our institution. All patients who received ICI alone or in combination with other systemic therapy in any line of treatment were included; those with thrombocytopenia ≥ grade 3 at baseline were excluded. We calculated the incidence of ≥ grade 3 irTCP and overall survival (OS). Patient factors associated with irTCP were assessed.

RESULTS

We identified 1,038 patients that met eligibility criteria. Overall, 89 (8.6%) patients developed grade ≥ 3 thrombocytopenia; eighteen were attributed to ICI (1.73% overall). Patients who developed grade ≥ 3 irTCP had worse overall survival compared to those whose thrombocytopenia was unrelated to ICI (4.17 vs. 10.8 month; HR. 1.94, 95% CI 1.13, 3.33; log-rank p = 0.0164). Patients with grade ≥ 3 irTCP also had worse survival compared to those without thrombocytopenia (4.17 vs. 13.31 months; HR 2.22, 95% CI 1.36, 3.62; log-rank p = 0.001). The incidence of irTCP appeared lowest among those treated with PD-1/L1 monotherapy (p = 0.059) and was not associated with cancer type, smoking status, age, gender, race, or line of therapy.

CONCLUSIONS

Unlike other irAEs, we found that irTCP was associated with worse overall survival. The incidence of irTCP appeared lowest among those treated with PD-1/L1 monotherapy.

Comparative assessment of manual chart review and ICD claims data in evaluating immunotherapy-related adverse events

BACKGROUND

The aim of this retrospective study was to demonstrate that irAEs, specifically gastrointestinal and pulmonary, examined through International Classification of Disease (ICD) data leads to underrepresentation of true irAEs and overrepresentation of false irAEs, thereby concluding that ICD claims data are a poor approach to electronic health record (EHR) data mining for irAEs in immunotherapy clinical research.

METHODS

This retrospective analysis was conducted in 1,063 cancer patients who received ICIs between 2011 and 2017. We identified irAEs by manual review of medical records to determine the incidence of each of our endpoints, namely colitis, hepatitis, pneumonitis, other irAE, or no irAE. We then performed a secondary analysis utilizing ICD claims data alone using a broad range of symptom and disease-specific ICD codes representative of irAEs.

RESULTS

16% (n = 174/1,063) of the total study population was initially found to have either pneumonitis 3% (n = 37), colitis 7% (n = 81) or hepatitis 5% (n = 56) on manual review. Of these patients, 46% (n = 80/174) did not have ICD code evidence in the EHR reflecting their irAE. Of the total patients not found to have any irAEs during manual review, 61% (n = 459/748) of patients had ICD codes suggestive of possible irAE, yet were not identified as having an irAE during manual review.

DISCUSSION

Examining gastrointestinal and pulmonary irAEs through the International Classification of Disease (ICD) data leads to underrepresentation of true irAEs and overrepresentation of false irAEs.

Refractory dermatitis contributed by pityriasis versicolor: a case report

Background

Dermatologic toxicity is a very common immune-related adverse event (irAE) for patients with melanoma who are receiving immune checkpoint inhibitor therapy (ICI). Concurrent skin infection, such as in the case of pityriasis versicolor reported here, can mimic and/or exacerbate dermatologic toxicity from irAE.

Case presentation

A 58-year-old Caucasian man with a history of pityriasis versicolor infection and metastatic melanoma received ICI therapy. He developed progressively worsening pruritic maculopapular lesions 22 weeks into his treatment that ultimately covered 40% of his body. He was diagnosed with dermatologic toxicity due to ICI therapy with concurrent pityriasis versicolor. He was initially started on topical steroid and topical antifungal cream but achieved minimum improvement. His treatment was then escalated to oral prednisone, but it only achieved modest control of his dermatitis. All subsequent attempts to wean him from oral prednisone resulted in worsening of his dermatitis. Eventually he was started on oral fluconazole in combination with prednisone, which led to rapid resolution of his dermatitis.

Conclusion

We report a case of dermatological toxicity due to an irAE with concurrent pityriasis versicolor. The steroid treatment for irAE was likely exacerbating the underlying fungal infection, and the fungal infection was in term mimicking the symptoms of irAE. This patient’s severe dermatitis was only brought under control after receiving a more potent antifungal therapy in combination with a steroid. It is vital to look beyond the irAE when managing dermatitis in patients receiving ICI therapy.

Three-year survival, correlates and salvage therapies in patients receiving first-line pembrolizumab for advanced Merkel cell carcinoma

Background

Merkel cell carcinoma (MCC) is an aggressive skin cancer associated with poor survival. Programmed cell death-1 (PD-1) pathway inhibitors have shown high rates of durable tumor regression compared with chemotherapy for MCC. The current study was undertaken to assess baseline and on-treatment factors associated with MCC regression and 3-year survival, and to explore the effects of salvage therapies in patients experiencing initial non-response or tumor progression after response or stable disease following first-line pembrolizumab therapy on Cancer Immunotherapy Trials Network-09/KEYNOTE-017.

Methods

In this multicenter phase II trial, 50 patients with advanced unresectable MCC received pembrolizumab 2 mg/kg every 3 weeks for ≤2 years. Patients were followed for a median of 31.8 months.

Results

Overall response rate to pembrolizumab was 58% (complete response 30%+partial response 28%; 95% CI 43.2 to 71.8). Among 29 responders, the median response duration was not reached (NR) at 3 years (range 1.0+ to 51.8+ months). Median progression-free survival (PFS) was 16.8 months (95% CI 4.6 to 43.4) and the 3-year PFS was 39.1%. Median OS was NR; the 3-year OS was 59.4% for all patients and 89.5% for responders. Baseline Eastern Cooperative Oncology Group performance status of 0, greater per cent tumor reduction, completion of 2 years of treatment and low neutrophil-to-lymphocyte ratio were associated with response and longer survival. Among patients with initial disease progression or those who developed progression after response or stable disease, some had extended survival with subsequent treatments including chemotherapies and immunotherapies.

Conclusions

This study represents the longest available follow-up from any first-line anti-programmed death-(ligand) 1 (anti-PD-(L)1) therapy in MCC, confirming durable PFS and OS in a proportion of patients. After initial tumor progression or relapse following response, some patients receiving salvage therapies survived. Improving the management of anti-PD-(L)1-refractory MCC remains a challenge and a high priority.

Trial registration number

NCT02267603.

NCCN Guidelines® Insights: Melanoma: Cutaneous, Version 2.2021

Over the past few years, the NCCN Guidelines for Melanoma: Cutaneous have been expanded to include pathways for treatment of microscopic satellitosis (added in v2.2020), and the following Principles sections: Molecular Testing (added in v2.2019), Systemic Therapy Considerations (added in v2.2020), and Brain Metastases Management (added in v3.2020). The v1.2021 update included additional modifications of these sections and notable revisions to Principles of: Pathology, Surgical Margins for Wide Excision of Primary Melanoma, Sentinel Lymph Node Biopsy, Completion/Therapeutic Lymph Node Dissection, and Radiation Therapy. These NCCN Guidelines Insights discuss the important changes to pathology and surgery recommendations, as well as additions to systemic therapy options for patients with advanced disease.

Abstract 4481: Effect of immune checkpoint blockade on myeloid derived suppressor cell populations in patients with melanoma

Introduction: Myeloid derived suppressor cells (MDSC) are a subset of immature myeloid cells that inhibit innate anti-tumor immunity and promote an immunosuppressive tumor microenvironment. MDSC quantity has been correlated with tumor burden and survival in cancer patients. These cells have the potential to contribute to immune therapy resistance. The purpose of this study was to elucidate the ongoing changes to MDSC populations in patients with advanced melanoma as they receive immune checkpoint therapy.

Methods: Patients with melanoma (n=125) were consented to participate in an IRB-approved prospective clinical registry (OSU-13114), and provided blood samples. Samples were drawn at the time of initiation of immune checkpoint therapy (cycle 1), and prior to the beginning of cycles 2 and 3. Samples were then processed using Ficoll and analyzed for MDSC (CD33+/CD11b+/HLA-DRlo/−) and MDSC subsets, monocyte (CD14+, M-MDSC) and granulocytic (CD15+, PMN-MDSC) via flow cytometry. Patient demographics were compiled into a comprehensive database and correlated to the flow cytometry data. Statistical analysis was performed using unpaired and paired t-tests across and within patient cohorts.

Results: Total MDSC percentages increased following initiation of immune checkpoint blockade (10 to 25%, p&lt;0.0001). MDSC levels in patients who had complete or partial response began to taper (10% to 26% to 25%), whereas MDSC levels in those who had progressive disease on immunotherapy continued to increase (11% to 16% to 19%). PMN-MDSC significantly decreased after immunotherapy (19% to 10%, p=0.0423). Specifically, patients who received Pembrolizumab had a significant decrease in PMN-MDSC proportion (11% to 2%, p=0.04). A decrease in PMN-MDSC proportion was also noted with Nivolumab (21% to 16%, p=0.097). Patients who had received immune therapy prior to this trial had less PMN-MDSC at baseline (21% vs 12%, p=0.09), and significantly less PMN-MDSC following immune checkpoint blockade (14% vs 2%, p=0.009).

Conclusions: MDSC levels initially increase following immune checkpoint blockade, but stabilize in responders and continue to rise in non-responders. The proportion of PMN-MDSC decreases with immune checkpoint blockade, most significantly seen with pembrolizumab. Patients who have been previously treated with immune therapy have a more significant decrease in PMN-MDSC.

Citation Format: Steven Hao Sun, Brooke Benner, Himanshu Savardekar, Mallory DiVincenzo, David Abood, Andrew Stiff, Megan Duggan, Erin Nagle, John H. Howard, Manisha H. Shah, Kari Kendra, William E. Carson. Effect of immune checkpoint blockade on myeloid derived suppressor cell populations in patients with melanoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4481.

Abstract CT013: SWOG S1320: Improved progression-free survival with continuous compared to intermittent dosing with dabrafenib and trametinib in patients with BRAF mutated melanoma

Background: BRAF and MEK inhibitors yield objective responses in the majority of BRAFV600E/K mutant melanoma patients, but acquired resistance limits response durations. Preclinical data suggests that intermittent dosing of these agents may delay acquired resistance by deselecting tumor cells that grow optimally in the presence of these agents. S1320 is a randomized phase 2 clinical trial designed to determine whether intermittent versus continuous dosing of dabrafenib and trametinib improves progression-free survival (PFS) in patients with advanced BRAFV600E/K melanoma.

Methods: All patients received continuous dabrafenib and trametinib for 8-weeks after which non-progressing patients were randomized to receive either continuous treatment or intermittent dosing of both drugs on a 3-week-off, 5-week-on schedule. Unscheduled treatment interruptions of both drugs for &gt; 14 days were not permitted. Responses were assessed using RECIST v1.1 at 8-week intervals scheduled to coincide with on-treatment periods for patients on the intermittent dosing arm. Adverse events were assessed using CTCAE v4 monthly. The design assumed exponential PFS with a median of 9.4 months using continuous dosing, 206 eligible patients and 156 PFS events. It had 90% power with a two-sided α = 0.2 to detect a change to a median with an a priori hypothesis that intermittent dosing would improve the median PFS to 14.1 months using a Cox model stratified by the randomization stratification factors.

Results: 242 patients were treated and 206 patients without disease progression after 8 weeks were randomized, 105 to continuous and 101 to intermittent treatment. 70% of patients had not previously received immune checkpoint inhibitors. There were no significant differences between groups in terms of baseline patient characteristics. The median PFS was statistically significantly longer, 9.0 months from randomization, with continuous dosing vs. 5.5 months from randomization with intermittent dosing (p = 0.064). There was no difference in overall survival between groups (median OS = 29.2 months in both arms p = 0.93) at a median follow up of 2 years. 77% of patient treated continuously discontinued treatment due to disease progression vs. 84% treated intermittently (p = 0.34).

Conclusions: Continuous dosing with the BRAF and MEK inhibitors dabrafenib and trametinib yields superior PFS compared with intermittent dosing.

Support: NIH/NCI grants CA180888, CA180819, CA180820

Citation Format: Alain Algazi, Megan Othus, Adil Daud, Roger Lo, Janice Mehnert, Thach-Giao Truong, Robert Conry, Kari Kendra, Gary Doolittle, Joseph I. Clark, Michael Messino, Dennis F. Moore, Christopher Lao, Bryan A. Faller, Rangaswamy Govindarajan, Amy Harker-Murray, Luke Dreisbach, James Moon, Kenneth Grossman, Antoni Ribas. SWOG S1320: Improved progression-free survival with continuous compared to intermittent dosing with dabrafenib and trametinib in patients with BRAF mutated melanoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT013.

Programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) expression in PD-1 inhibitor-associated colitis and its mimics

AIMS

Immune checkpoint inhibitors (ICIs) have revolutionised the treatment of advanced malignancies by boosting immune-mediated destruction of neoplastic cells, but are associated with side effects stemming from generalised immune system activation against normal tissues. Checkpoint ligand expression in non-tumoral cells of tissues affected by immune-related adverse effects has been described in ICI-associated hypophysitis, myocarditis, and acute interstitial nephritis. We aimed to investigate the tissue expression of the immune checkpoint receptor programmed cell death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), in PD-1 inhibitor-associated colitis (PD1i colitis).

METHODS AND RESULTS

PD-1 and PD-L1 immunohistochemical expression levels were analysed in 15 cases of PD1i colitis and potential mimics-infectious colitis and inflammatory bowel disease (IBD). Increased epithelial expression of PD-L1 was observed in PD1i colitis as compared with normal colon and infectious colitis, but the expression level was lower than that in IBD. Conversely, PD-1 expression in inflammatory cells was higher in infectious colitis, intermediate in IBD, and minimal or absent in normal colon and in patients receiving PD-1 inhibitors.

CONCLUSIONS

Although our results do not justify the use of PD-L1 as a discriminatory marker of PD1i colitis against other entities within the differential diagnosis, they support the concept that PD1i colitis and IBD have similar pathogenetic mechanisms. They also highlight the fact that PD-L1 epithelial overexpression is a commonly used mechanism of the gastrointestinal tract mucosa to protect itself from inflammatory-mediated damage resulting from different aetiologies, which probably underpins the high incidence of gastrointestinal immune-related adverse effects in patients receiving ICI therapies, in whom this mechanism is disrupted.

Change in neutrophil to lymphocyte ratio during immunotherapy treatment is a non-linear predictor of patient outcomes in advanced cancers

BACKGROUND

The neutrophil to lymphocyte ratio (NLR) is known to be prognostic for patients with advanced cancers treated with immune checkpoint inhibitors (ICI), but has generally been evaluated as a single threshold value at baseline. We evaluated NLR at baseline and within first month during treatment in patients who received ICI for advanced cancer to evaluate the prognostic value of baseline and of changes from baseline to on-treatment NLR.

METHODS

A retrospective review of patients with advanced cancer treated with ICI from 2011 to 2017 at the Ohio State University was performed. NLR was calculated at the initiation of ICI and repeated at median of 21 days. Overall survival (OS) was calculated from the initiation of ICI to date of death or censored at last follow-up. Significance of Cox proportional hazards models were evaluated by log-rank test. Calculations were performed using the survival and survminer packages in R, and SPSS.

RESULTS

509 patients were identified and included in the analysis. Patients with baseline and on-treatment NLR < 5 had significantly longer OS (P < 0.001). The change in NLR overtime was a predictor of OS and was observed to be non-linear in nature. This property remained statistically significant with P < 0.05 after adjusting for age, body mass index, sex, cancer type, performance status, and days to repeat NLR measurement. Patients with a moderate decrease in NLR from baseline had the longest OS of 27.8 months (95% CI 21.8-33.8). Patients with significant NLR decrease had OS of 11.4 months (95% CI 6.1-16.7). Patients with a significant increase in NLR had the shortest OS of 5.0 months (95% CI 0.9-9.1).

CONCLUSIONS

We confirmed the prognostic value of NLR in patients with advanced cancer treated with ICIs. We found that change in NLR over time is a non-linear predictor of patient outcomes. Patients who had moderate decrease in NLR during treatment with ICI were found to have the longest survival, whereas a significant decrease or increase in NLR was associated with shorter survival. To our knowledge, this is the first study to demonstrate a non-linear change in NLR over time that correlates with survival.

Resumption of Immune Checkpoint Inhibitor Therapy After Immune-Mediated Colitis

PURPOSE

Immune checkpoint inhibitor (ICI) therapy often is suspended because of immune-mediated diarrhea and colitis (IMDC). We examined the rate of and risk factors for IMDC recurrence after ICI resumption.

METHODS

This retrospective multicenter study examined patients who resumed ICI therapy after improvement of IMDC between January 2010 and November 2018. Univariable and multivariable logistic regression analyses assessed the association of clinical covariates and IMDC recurrence.

RESULTS

Of the 167 patients in our analysis, 32 resumed an anti–cytotoxic T-cell lymphocyte-4 (CTLA-4) agent, and 135 an anti–programmed cell death 1 or ligand 1 (PD-1/L1) agent. The median age was 60 years (interquartile range [IQR], 50-69 years). The median duration from IMDC to restart of ICI treatment was 49 days (IQR, 23-136 days). IMDC recurred in 57 patients (34%) overall (44% of those receiving an anti–CTLA-4 and 32% of those receiving an anti–PD-1/L1); 47 of these patients (82%) required immunosuppressive therapy for recurrent IMDC, and all required permanent discontinuation of ICI therapy. The median duration from ICI resumption to IMDC recurrence was 53 days (IQR, 22-138 days). On multivariable logistic regression, patients who received anti–PD-1/L1 therapy at initial IMDC had a higher risk of IMDC recurrence (odds ratio [OR], 3.45; 95% CI, 1.59 to 7.69; P = .002). Risk of IMDC recurrence was higher for patients who required immunosuppression for initial IMDC (OR, 3.22; 95% CI, 1.08 to 9.62; P = .019) or had a longer duration of IMDC symptoms in the initial episode (OR, 1.01; 95% CI, 1.00 to 1.03; P = .031). Risk of IMDC recurrence was lower after resumption of anti–PD-1/L1 therapy than after resumption of anti–CTLA-4 therapy (OR, 0.30; 95% CI, 0.11 to 0.81; P = .019).

CONCLUSION

One third of patients who resumed ICI treatment after IMDC experienced recurrent IMDC. Recurrence of IMDC was less frequent after resumption of anti–PD-1/L1 than after resumption of anti–CTLA-4.

Hybrid Capture-Based Genomic Profiling Identifies BRAF V600 and Non-V600 Alterations in Melanoma Samples Negative by Prior Testing

BACKGROUND

BRAF and MEK inhibitors are approved for BRAF V600-mutated advanced melanoma, with response rates of up to 70%. Responses to targeted therapies have also been observed for diverse non-V600 BRAF alterations. Thus, sensitive, accurate, and broad detection of BRAF alterations is critical to match patients with available targeted therapies.

MATERIALS AND METHODS

Pathology reports were reviewed for 385 consecutive melanoma cases with BRAF mutations or rearrangements identified using a hybrid capture-based next-generation sequencing comprehensive genomic profiling (CGP) assay during the course of clinical care.

RESULTS

Records of prior BRAF molecular testing were available for 79 (21%) cases. Of cases with BRAF V600 mutations, 11/57 (19%) with available data were negative by prior BRAF testing. Prior negative BRAF results were also identified in 16/20 (80%) cases with non-V600 mutations, 2 of which harbored multiple BRAF alterations, and in 2/2 (100%) cases with activating BRAF fusions. Clinical outcomes for a subset of patients are presented.

CONCLUSION

CGP identifies diverse activating BRAF alterations in a significant fraction of cases with prior negative testing. Given the proven clinical benefit of BRAF/MEK inhibitors in BRAF-mutated melanoma, CGP should be considered for patients with metastatic melanoma, particularly if other testing is negative.

IMPLICATIONS FOR PRACTICE

Published guidelines for melanoma treatment recommend BRAF mutational analysis, but little guidance is provided as to selection criteria for testing methodologies, or as to clinical implications for non-V600 alterations. This study found that hybrid capture-based next-generation sequencing can detect BRAF alterations in samples from a significant fraction of patients with advanced melanoma with prior negative BRAF results. This study highlights the need for oncologists and pathologists to be critically aware of coverage and sensitivity limitations of various assays, particularly regarding non-V600E alterations, of which many are potentially targetable.

Phase I Trial of Dabrafenib and Pazopanib in BRAF Mutated Advanced Malignancies

Purpose

Several tumor types carry BRAF mutations and vascular endothelial growth factor pathway upregulation. Resistance mechanisms to BRAF inhibitors can include platelet-derived growth factor-β upregulation. Dabrafenib, a BRAF inhibitor, and pazopanib, a multikinase inhibitor that targets vascular endothelial growth factor and platelet-derived growth factor, have not been combined previously. This phase I study was designed to evaluate the safety, pharmacokinetics, and pharmacodynamics of the combination.

Patients and Methods

Patients with any advanced BRAF mutated malignancy with adequate organ function were eligible. Prior use of dabrafenib or pazopanib was not allowed. Dosages started at dabrafenib 50 mg twice a day and pazopanib 400 mg daily on dose level (DL) 1, with maximum dosages of 150 mg twice a day and 800 mg daily on DL5. Pharmacokinetics and BRAF V600E plasma clone were measured, and efficacy was evaluated by imaging and tumor markers every 8 weeks.

Results

Twenty-three patients with 11 different tumor histologies were enrolled in five DLs. Two dose-limiting toxicities were observed—a grade 3 bowel perforation on DL3 and grade 3 arthralgia on DL5. Common drug-related adverse events included nausea (52%), skin papules (43%), diarrhea (39%), hand-foot syndrome (30%), anemia (26%), rash (22%), vomiting (22%), hypophosphatemia (22%), and transaminitis (22%). Five patients (22%) experienced a partial response, including low-grade ovarian serous carcinoma, thyroid cancer, and glioblastoma multiforme, and two patients (appendiceal and thyroid cancer) had stable disease > 6 months. Pharmacokinetic measurements revealed pazopanib levels < 17.5 μg/mL in 80% of treated patients at steady state, particularly at DL5. BRAF V600E plasma copies correlated with response and progression.

Conclusion

Combination dabrafenib and pazopanib had no unexpected toxicities, and durable partial responses were observed at DL3 or greater. Dose escalation beyond DL5 may be considered as pazopanib levels were suboptimal as a result of drug interaction with dabrafenib.

Nitric Oxide Production by Myeloid-Derived Suppressor Cells Plays a Role in Impairing Fc Receptor-Mediated Natural Killer Cell Function

Purpose: mAbs are used to treat solid and hematologic malignancies and work in part through Fc receptors (FcRs) on natural killer cells (NK). However, FcR-mediated functions of NK cells from patients with cancer are significantly impaired. Identifying the mechanisms of this dysfunction and impaired response to mAb therapy could lead to combination therapies and enhance mAb therapy.Experimental Design: Cocultures of autologous NK cells and MDSC from patients with cancer were used to study the effect of myeloid-derived suppressor cells (MDSCs) on NK-cell FcR-mediated functions including antibody-dependent cellular cytotoxicity, cytokine production, and signal transduction in vitro Mouse breast cancer models were utilized to study the effect of MDSCs on antibody therapy in vivo and test the efficacy of combination therapies including a mAb and an MDSC-targeting agent.Results: MDSCs from patients with cancer were found to significantly inhibit NK-cell FcR-mediated functions including antibody-dependent cellular cytotoxicity, cytokine production, and signal transduction in a contact-independent manner. In addition, adoptive transfer of MDSCs abolished the efficacy of mAb therapy in a mouse model of pancreatic cancer. Inhibition of iNOS restored NK-cell functions and signal transduction. Finally, nonspecific elimination of MDSCs or inhibition of iNOS in vivo significantly improved the efficacy of mAb therapy in a mouse model of breast cancer.Conclusions: MDSCs antagonize NK-cell FcR-mediated function and signal transduction leading to impaired response to mAb therapy in part through nitric oxide production. Thus, elimination of MDSCs or inhibition of nitric oxide production offers a strategy to improve mAb therapy. Clin Cancer Res; 24(8); 1891-904. ©2018 AACR.

Skin cancer screening: recommendations for data-driven screening guidelines and a review of the US Preventive Services Task Force controversy

Melanoma is usually apparent on the skin and readily detected by trained medical providers using a routine total body skin examination, yet this malignancy is responsible for the majority of skin cancer-related deaths. Currently, there is no national consensus on skin cancer screening in the USA, but dermatologists and primary care providers are routinely confronted with making the decision about when to recommend total body skin examinations and at what interval. The objectives of this paper are: to propose rational, risk-based, data-driven guidelines commensurate with the US Preventive Services Task Force screening guidelines for other disorders; to compare our proposed guidelines to recommendations made by other national and international organizations; and to review the US Preventive Services Task Force's 2016 Draft Recommendation Statement on skin cancer screening.

The Exportin-1 Inhibitor Selinexor Exerts Superior Antitumor Activity when Combined with T-Cell Checkpoint Inhibitors

Selinexor, a selective inhibitor of nuclear export (SINE) compound targeting exportin-1, has previously been shown to inhibit melanoma cell growth in vivo We hypothesized that combining selinexor with antibodies that block or disrupt T-cell checkpoint molecule signaling would exert superior antimelanoma activity. In vitro, selinexor increased PDCD1 and CTLA4 gene expression in leukocytes and induced CD274 gene expression in human melanoma cell lines. Mice bearing syngeneic B16F10 melanoma tumors demonstrated a significant reduction in tumor growth rate in response to the combination of selinexor and anti-PD-1 or anti-PD-L1 antibodies (P < 0.05). Similar results were obtained in B16F10-bearing mice treated with selinexor combined with anti-CTLA4 antibody. Immunophenotypic analysis of splenocytes by flow cytometry revealed that selinexor alone or in combination with anti-PD-L1 antibody significantly increased the frequency of both natural killer cells (P ≤ 0.050) and CD4+ T cells with a Th1 phenotype (P ≤ 0.050). Further experiments indicated that the antitumor effect of selinexor in combination with anti-PD-1 therapy persisted under an alternative dosing schedule but was lost when selinexor was administered daily. These data indicate that the efficacy of selinexor against melanoma may be enhanced by disrupting immune checkpoint activity. Mol Cancer Ther; 16(3); 417-27. ©2017 AACRSee related article by Tyler et al., p. 428.

Abstract 553: Ibrutinib, a BTK inhibitor, impairs the generation and function of myeloid derived suppressor cells

Myeloid derived suppressor cells (MDSC) interfere with anti tumor immune responses. MDSC have also been shown to antagonize the effectiveness of immune based therapies including immune checkpoint blockade. As a result, MDSC have received attention as potential targets for immune based combination therapies. There has been limited success in the identification of clinically active agents with the ability to inhibit the function or generation of MDSC. Ibrutinib is an orally available irreversible inhibitor of Bruton's tyrosine kinase (BTK) that is FDA approved for the treatment of B cell malignancies. In addition to B cells, cells of the myeloid lineage including monocytes and macrophages express BTK, and treatment with ibrutinib has been shown to alter their function and differentiation. As a result, it was hypothesized that ibrutinib would interfere with the function or generation of MDSC in the setting of cancer. MDSC isolated from the spleens of multiple murine tumor models (EMT6, 4T1, and C26) as well as MDSC from patients with metastatic melanoma expressed BTK. Treatment with ibrutinib at doses ranging from 0.1-5 μM inhibited the phosphorylation of BTK in both murine and human MDSC. Ibrutinib treatment of murine and human MDSC resulted in a significant reduction in nitric oxide (NO) production (p&lt; 0.05), but had only modest effects on MDSC levels of IDO and arginase. Ibrutinib was also able to inhibit murine MDSC migration in response to EMT6 cell line conditioned media and the chemokine CXCL12 (p&lt; 0.05). In addition, ibrutinib inhibited human MDSC migration in response to GM CSF (p&lt; 0.05). Ibrutinib reduced the expression of the myeloid adhesion molecules CD11a (p&lt; 0.05) and CD49D (p&lt; 0.01) by MDSC, which could explain the reduction in migration. Importantly, ibrutinib significantly reduced the ability of MDSC to suppress CD8+ T cell proliferation compared to DMSO (21.98% vs. 12.49% proliferation, p&lt; 0.05). Daily treatment with ibrutinib effectively inhibited the in vitro generation of human MDSC from monocytes by promoting HLA DR expression (p&lt; 0.05). Using the EMT6 mammary carcinoma model in vivo, ibrutinib treatment resulted in a significant reduction of MDSC in both the spleen and tumor (p&lt; 0.05). Ibrutinib also reduced the frequency of splenic MDSC in wild type B16F10 tumor bearing mice, but not in BTK mutant XID mice. In addition, both murine and human MDSC did not express significant levels of alternative ibrutinib targets including ITK, Bmx, and Blk. These results suggest that inhibition of BTK is the primary driver behind the observed effects of ibrutinib on MDSC function and generation. Finally, the combination of ibrutinib and anti PDL1 therapy was significantly more effective than either agent alone (p&lt; 0.01 and p&lt; 0.05) producing complete tumor regression in 50% of EMT6 tumor being mice. The results support further investigation of ibrutinib in combination with immune based therapies for solid tumors.

Citation Format: Andrew R. Stiff, Prashant Trikha, Robert Wesolowski, Kari Kendra, Sarvani Uppati, David Abood, Elizabeth McMichael, Megan Duggan, Amanda Campbell, Natarajan Muthusamy, Susheela Tridandapani, Michael Caliguiri, John C. Byrd, William E. Carson. Ibrutinib, a BTK inhibitor, impairs the generation and function of myeloid derived suppressor cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 553.

Myeloid-Derived Suppressor Cells Express Bruton's Tyrosine Kinase and Can Be Depleted in Tumor-Bearing Hosts by Ibrutinib Treatment

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of immature myeloid cells that expand in tumor-bearing hosts in response to soluble factors produced by tumor and stromal cells. MDSC expansion has been linked to loss of immune effector cell function and reduced efficacy of immune-based cancer therapies, highlighting the MDSC population as an attractive therapeutic target. Ibrutinib, an irreversible inhibitor of Bruton's tyrosine kinase (BTK) and IL2-inducible T-cell kinase (ITK), is in clinical use for the treatment of B-cell malignancies. Here, we report that BTK is expressed by murine and human MDSCs, and that ibrutinib is able to inhibit BTK phosphorylation in these cells. Treatment of MDSCs with ibrutinib significantly impaired nitric oxide production and cell migration. In addition, ibrutinib inhibited in vitro generation of human MDSCs and reduced mRNA expression of indolamine 2,3-dioxygenase, an immunosuppressive factor. Treatment of mice bearing EMT6 mammary tumors with ibrutinib resulted in reduced frequency of MDSCs in both the spleen and tumor. Ibrutinib treatment also resulted in a significant reduction of MDSCs in wild-type mice bearing B16F10 melanoma tumors, but not in X-linked immunodeficiency mice (XID) harboring a BTK mutation, suggesting that BTK inhibition plays an important role in the observed reduction of MDSCs in vivo Finally, ibrutinib significantly enhanced the efficacy of anti-PD-L1 (CD274) therapy in a murine breast cancer model. Together, these results demonstrate that ibrutinib modulates MDSC function and generation, revealing a potential strategy for enhancing immune-based therapies in solid malignancies. Cancer Res; 76(8); 2125-36. ©2016 AACR.

A randomized, controlled phase III trial of nab-Paclitaxel versus dacarbazine in chemotherapy-naïve patients with metastatic melanoma

BACKGROUND

The efficacy and safety of nab-paclitaxel versus dacarbazine in patients with metastatic melanoma was evaluated in a phase III randomized, controlled trial.

PATIENTS AND METHODS

Chemotherapy-naïve patients with stage IV melanoma received nab-paclitaxel 150 mg/m(2) on days 1, 8, and 15 every 4 weeks or dacarbazine 1000 mg/m(2) every 3 weeks. The primary end point was progression-free survival (PFS) by independent radiologic review; the secondary end point was overall survival (OS).

RESULTS

A total of 529 patients were randomized to nab-paclitaxel (n = 264) or dacarbazine (n = 265). Baseline characteristics were well balanced. The majority of patients were men (66%), had an Eastern Cooperative Oncology Group status of 0 (71%), and had M1c stage disease (65%). The median PFS (primary end point) was 4.8 months with nab-paclitaxel and 2.5 months with dacarbazine [hazard ratio (HR), 0.792; 95.1% confidence interval (CI) 0.631-0.992; P = 0.044]. The median OS was 12.6 months with nab-paclitaxel and 10.5 months with dacarbazine (HR, 0.897; 95.1% CI 0.738-1.089; P = 0.271). Independently assessed overall response rate was 15% versus 11% (P = 0.239), and disease control rate (DCR) was 39% versus 27% (P = 0.004) for nab-paclitaxel versus dacarbazine, respectively. The most common grade ≥3 treatment-related adverse events were neuropathy (nab-paclitaxel, 25% versus dacarbazine, 0%; P < 0.001), and neutropenia (nab-paclitaxel, 20% versus dacarbazine, 10%; P = 0.004). There was no correlation between secreted protein acidic and rich in cysteine (SPARC) status and PFS in either treatment arm.

CONCLUSIONS

nab-Paclitaxel significantly improved PFS and DCR compared with dacarbazine, with a manageable safety profile.

Cotreatment of hairy cell leukemia and melanoma with the BRAF inhibitor dabrafenib

The activating BRAF mutation p.V600E has been identified in many cancers, including colon and lung adenocarcinomas, papillary thyroid cancer, malignant melanoma, and hairy cell leukemia (HCL). Malignant melanoma and HCL are of particular interest because of both the high proportion of cases harboring the mutation and the dramatic responses to BRAF inhibitor therapy reported in the literature. This report presents a patient with HCL and malignant melanoma with the BRAF p.V600E mutation, and discusses the successful treatment of both cancers with the BRAF inhibitor dabrafenib.

Abstract 3656: MDSC-generated nitric oxide leads to an impairment of NK cell functions in metastatic melanoma patients

Myeloid-derived suppressor cells (MDSCs) are able to inhibit the function of immune cells within the tumor microenvironment. The interaction of MDSCs with T cells has been studied extensively. However, the interaction of MDSCs with innate immune cells such as NK cells is not well understood. This study investigated whether the presence of MDSCs could impair the function of NK cells.

MDSC (CD33+HLA-DRneg/lowCD11b+) and autologous NK cells (CD56+CD3neg) were isolated from the peripheral blood of metastatic melanoma patients and co-cultured overnight at a 1:1 ratio (2 x 105 cells each). Culture with MDSC led to a 70% decrease in NK cell mediated antibody dependent cellular cytotoxicity (ADCC) against HER2+ SkBr3 cells coated with an anti-HER2 antibody and a two-fold decrease in the production of interferon-gamma in response to these targets. Stimulation of the NK cell Fc receptor by immobilized immunoglobulin G (IgG) led to phosphorylation of Erk (p-Erk) and this event was significantly inhibited in the presence of MDSC in a dose and contact-dependent manner (p&lt;0.05). Co-culture of NK cells with MDSC also led to reduced expression of the NKp30 activating receptor (1.7-fold decrease) and a decrease in cytotoxicity against the K562 cell line. MDSC were able to generate significant levels of nitric oxide (NO) and inhibition of MDSC NO synthesis in co-cultures led to a significant improvement in NK cell cytotoxicity and cytokine production (p&lt;0.05). Depletion of MDSC from BALB/c mice bearing tumors of the CT26 adenocarcinoma cell line led to a three-fold increase in NK cell mediated ADCC. These results demonstrate that MDSC-derived NO can inhibit NK cell function, and suggest that strategies aimed at eliminating or deactivating MDSC may lead to enhanced efficacy of immune based therapies.

Citation Format: Prashant Trikha, Bethany Mundy-Bosse, Ian Landi, Elizabeth McMichael, Amanda Harper, Megan Duggan, Nancy Stasik, Kari Kendra, Thomas Olencki, William Carson. MDSC-generated nitric oxide leads to an impairment of NK cell functions in metastatic melanoma patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3656. doi:10.1158/1538-7445.AM2014-3656

Novel small molecule XPO1/CRM1 inhibitors induce nuclear accumulation of TP53, phosphorylated MAPK and apoptosis in human melanoma cells

XPO1/CRM1 is a key nuclear exporter protein that mediates translocation of numerous cellular regulatory proteins. We investigated whether XPO1 is a potential therapeutic target in melanoma using novel selective inhibitors of nuclear export (SINE). In vitro effects of SINE on cell growth and apoptosis were measured by MTS assay and flow cytometry [Annexin V/propidium iodide (PI)], respectively in human metastatic melanoma cell lines. Immunoblot analysis was used to measure nuclear localization of key cellular proteins. The in vivo activity of oral SINE was evaluated in NOD/SCID mice bearing A375 or CHL-1 human melanoma xenografts. SINE compounds induced cytostatic and pro-apoptotic effects in both BRAF wild type and mutant (V600E) cell lines at nanomolar concentrations. The cytostatic and pro-apoptotic effects of XPO1 inhibition were associated with nuclear accumulation of TP53, and CDKN1A induction in the A375 cell line with wild type TP53, while pMAPK accumulated in the nucleus regardless of TP53 status. The orally bioavailable KPT-276 and KPT-330 compounds significantly inhibited growth of A375 (p<0.0001) and CHL-1 (p = 0.0087) human melanoma cell lines in vivo at well tolerated doses. Inhibition of XPO1 using SINE represents a potential therapeutic approach for melanoma across cells with diverse molecular phenotypes by promoting growth inhibition and apoptosis.

Development and validation of sensitive liquid chromatography/tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue

A liquid chromatography-tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue was developed and fully validated. Methanol was used to precipitate proteins in brain tissue. Bendamustine and internal standard (chlorambucil) were separated with reverse-phase chromatography on a C-18 column with a gradient of water and 95% methanol in 0.1% formic acid. Positive mode electrospray ionization was applied with selected reaction monitoring to achieve 5 ng/ml lower limits of quantitation in mouse brain tissue. The calibration curve for bendamustine in mouse brain was linear between 5 and 2000 ng/ml. The within- and between-batch accuracy and precision of the assay were within 15% at 10, 100 and 1000 ng/ml. The recovery and matrix effect of bendamustine in mouse brain tissue ranged from 41.1% to 51.6% and 107.4% to 110.3%, respectively. The validated method was then applied to quantitate bendamustine in an animal study. Results indicate the assay can be applied to evaluate bendamustine disposition in mouse brain tissue. This assay will be applied in the future to detect and quantify bendamustine in human brain tissue samples.

Gene expression profiling reveals similarities between the in vitro and in vivo responses of immune effector cells to IFN-alpha

PURPOSE

The precise molecular targets of IFN-alpha therapy in the context of malignant melanoma are unknown but seem to involve signal transducers and activators of transcription 1 signal transduction within host immune effector cells. We hypothesized that the in vitro transcriptional response of patient peripheral blood mononuclear cells (PBMC) to IFN-alpha would be similar to the in vivo response to treatment with high-dose IFN-alpha.

EXPERIMENTAL DESIGN

The gene expression profiles of PBMCs and immune cell subsets treated in vitro with IFN-alpha were evaluated, as were PBMCs obtained from melanoma patients receiving adjuvant IFN-alpha.

RESULTS

Twenty-seven genes were up-regulated in PBMCs from normal donors after treatment with IFN-alpha in vitro for 18 hours (>2-fold, P < 0.001). A subset of these genes (in addition to others) was significantly expressed in IFN-alpha-treated T cells, natural killer cells, and monocytes. Analysis of gene expression within PBMCs from melanoma patients (n = 13) receiving high-dose IFN-alpha-2b (20 MU/m(2) i.v.) revealed significant up-regulation (>2-fold) of 21 genes (P < 0.001). Also, the gene expression profile of in vitro IFN-alpha-stimulated patient PBMCs was similar to that of PBMCs obtained from the same patient after IFN-alpha therapy.

CONCLUSIONS

This report is the first to describe the transcriptional response of T cells, natural killer cells, and monocytes to IFN-alpha and characterize the transcriptional profiles of PBMCs from melanoma patients undergoing IFN-alpha immunotherapy. In addition, it was determined that microarray analysis of patient PBMCs after in vitro stimulation with IFN-alpha may be a useful predictor of the in vivo response of immune cells to IFN-alpha immunotherapy.

Activation of extracellular signaling regulated kinase in natural killer cells and monocytes following IL-2 stimulation in vitro and in patients undergoing IL-2 immunotherapy: analysis via dual parameter flow-cytometric assay

Interleukin-2 (IL-2) activates extracellular signal-regulated protein kinase (ERK) within immune cells. To examine the profile of phosphorylated ERK (p-ERK) in IL-2 stimulated immune cells of normal donors and patients receiving IL-2 therapy, we developed a dual parameter flow-cytometric assay. An analysis of PBMCs stimulated with IL-2 indicated that IL-2 exposure induced p-ERK in CD56bright NK cells and CD14+ monocytes, but not in CD3+ T cells or CD21+ B cells. CD3+ T cells that were induced to express functional high-affinity IL-2R did not exhibit enhanced p-ERK following IL-2 treatment. Measurement of p-ERK within PBMCs from cancer patients 1 h following their first dose of IL-2 revealed a complete absence of circulating NK cells, consistent with earlier observations. However, the total number of circulating CD14+ monocytes increased in these samples and 97% of these cells exhibited ERK activation. p-ERK was not observed in T cells post-IL-2 therapy. Analysis of PBMCs obtained 3 weeks post-IL-2 therapy revealed high-p-ERK levels in CD56bright NK cells in a subset of patients, while levels of p-ERK returned to baseline in monocytes. These studies reveal an effective method to detect ERK activation in immune cells and demonstrate that IL-2 activates ERK in a subset of NK cells and monocytes but not T cells.

Randomized phase II adjuvant trial of dose-dense docetaxel before or after doxorubicin plus cyclophosphamide in axillary node-positive breast cancer

PURPOSE

An anthracycline-based combination followed by, or combined with, a taxane is the sequence used in most adjuvant chemotherapy regimens. We hypothesized that administering the taxane before the anthracycline combination would be associated with fewer dose reductions and delays than the reverse sequence. To test this hypothesis, a randomized phase II multicenter adjuvant chemotherapy trial was performed.

PATIENTS AND METHODS

Fifty-six patients with axillary node-positive, nonmetastatic breast cancer were randomly assigned either to group A (docetaxel [DOC] 75 mg/m(2) intravenously [IV] every 14 days for four cycles followed by doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) [AC] IV every 14 days for four cycles); or to group B (AC followed by DOC) at the identical doses and schedule. Pegfilgrastim 6 mg subcutaneous injection was administered 1 day after the chemotherapy in all treatment cycles. The primary objective was to administer DOC without dose reductions or delays before or after AC and calculate the relative dose intensity (RDI) of DOC and AC.

RESULTS

The majority of toxicities were grade 0 to 2 irrespective of sequence. The RDI for DOC was 0.96 and 0.82, respectively, in groups A (DOC followed by AC) and B (AC followed by DOC), with more frequent dose reductions occurring in group B (46% v 18%). The RDI for AC was 0.95 and 0.98 in groups A and B, respectively.

CONCLUSION

The administration of DOC before AC results in fewer DOC dose reductions and a higher RDI than the reverse sequence. Larger trials evaluating the sequence of DOC before anthracyclines are justified.